The number of red cards in Lyle's trading card collection is directly is proportional to the number of yellow cards. At one point, Lyle's collection consisted of 56 red cards and 224 yellow cards. If r represent the number of red cards, and s represents the number of yellow cards,which equation best represents Lyle's collection.
A. r= 1/4s
B. r= s-168
C. r= 5/4s - 224
D. r= 224-s
"The number of red cards in Lyle's trading card collection is directly is proportional to the number of yellow cards" ---> r = ks , were k is a constant
given: when r=56 , s=224
56 = k(224)
k = 56/224 = 1/4
so r = (1/4)s